US4328419A - Photo-electric detector with temperature-compensated circuit - Google Patents

Photo-electric detector with temperature-compensated circuit Download PDF

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Publication number
US4328419A
US4328419A US06/152,250 US15225080A US4328419A US 4328419 A US4328419 A US 4328419A US 15225080 A US15225080 A US 15225080A US 4328419 A US4328419 A US 4328419A
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Prior art keywords
photo
coupled
resistance
circuit
transistor
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US06/152,250
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English (en)
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Marcel Lefebvre
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Telemecanique SA
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Telemecanique Electrique SA
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/941—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated using an optical detector
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/26—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback
    • H03K3/28—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback
    • H03K3/281—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator
    • H03K3/282—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator astable
    • H03K3/2826—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator astable using two active transistors of the complementary type
    • H03K3/2828—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator astable using two active transistors of the complementary type in an asymmetrical circuit configuration

Definitions

  • the invention relates to photo-electric detectors of the presence of an object, of the type comprising an electro-luminescent diode excited by an emitter circuit and coupled to a photo-electric receiver, a circuit for integrating the current delivered by the receiver, a thyristor switching means, controlled by the integrated current, a utilisation means and a means for feeding from the sector. It concerns more particularly the devices known as "two wire", in which the switching means is connected to the terminals of non-filtered rectified current of a diode bridge connected to the sector by the utilisation means. This latter is for example a relay controlled by the switching means.
  • This type of detector of which the industrial applications are numerous (for example, detection of the passage of an object in the luminous beam emitted by the electro-luminescent diode in the direction of the receiver, for the purpose of initiating a certain operation) has a range of several meters, greater than that of a detector with inductive receiver.
  • the use, well known in such a circuit, of an electro-luminescent diode permits one to do without employing a feed transformer, and thus to reduce the bulk and the consumption of electrical energy.
  • the switching means When it is desired, for purposes of simplification of the circuit, to construct it in the "two wire" version, it is necessary to face up to two known difficulties.
  • the first is that, when the switching means is in the blocked state, the current consumed by the receiver assembly (which comprises the electro-luminescent diode, the receiver and the integrator circuit) passes through the utilisation means, as a result of which this current must be reduced as much as possible.
  • the second difficulty is that, when the switching means is conductive, it is necessary to provide an auxiliary source of feed voltage for the receiver.
  • the multivibrator being of the type with two complementary transistors of which the base of the first is coupled to the collector of the second by a resistance capacity time constant circuit
  • the resistance comprises a resistance with negative temperature coefficient of value such that the variations of duration of conduction due to variations of the said time constant and those due to the gain of the first transistor are substantially compensated for in regard to temperature.
  • the value of the resistance with negative temperature coefficient is selected such that the said duration of conduction increases slightly when the temperature decreases, in order to compensate for the loss of photo-electric sensitivity of the photo-transistor at low temperatures.
  • the invention provides a particularly simple circuit likewise requiring an auxiliary thyristor, the said circuit being arranged so that, when the said auxiliary thyristor becomes unblocked and before it causes unblocking of the principal thyristor, a condenser connected in series with the auxiliary thyristor to the rectifier terminals of the diode bridge can charge up during a brief interval of time across the said auxiliary thyristor and a diode which couples the cathode of the said auxiliary thyristor to the positive pole of the said condenser.
  • FIGURE of drawing shows the layout of the circuits of a photo-electric detector conforming to a preferred manner of carrying out the invention.
  • the circuit shown comprises, in known manner: an emitter of luminous impulses constituted by an electro-luminescent diode D 1 mounted in the circuit of a multivibrator comprising two complementary transistors T 3 , T 4 ; a receiver comprising a photo-transistor T 1 and an amplifying transistor T 2 ; an integrator comprising resistances R 22 , R 23 , R 24 and condensors C 7 and C 8 , and a thyristor switching device which comprises here two thyristors Th 1 and Th 2 and a transistor T 8 .
  • the feed voltage is provided by a bridge of diodes D 11 to D 14 connected to the network across the load, not shown, the circuit being of the two wire type.
  • the base of the transistor T 8 which is of the NPN type (as are the other transistors of the circuit given by way of example, with the exception of T 3 and T 6 ) is coupled on the one hand to a collector of the transistor T 2 by means of a condensor C 5 and of a resistance R 16 , and on the other hand to the common point of the resistances R 23 and R 24 and the condensor C 8 .
  • the condenser C 9 firstly charges itself across a diode D 17 which couples one of its electrodes to the point A common to the cathode of Th 1 and that of the Zener diode D 7 . As soon as the voltage at A reaches a value, for example 8.2 volts, which corresponds to the inverse voltage of the Zener diode D 7 , this latter goes to output which causes a rise in voltage of the striker of Th 2 , taken to the terminals of R 29 , until there is a sufficient value for the said thyristor to fire. Th 2 , which is advantageously of a calibre greater than Th 1 , thus takes over from the latter. Obviously C 9 stops charging.
  • the transistor T 8 When the beam is not broken, the transistor T 8 is in the saturated condition, because the voltage of the striker of Th 1 is of the order of 0.8 v. (the sum of the voltage drops in D 15 and T 8 ). Th 1 is thus in the blocked condition so that the striker of Th 2 is at earth and this latter thyristor is itself blocked. This blocking is assisted by the presence of a diode D 8 between the cathode of Th 2 and earth. During the intervals of time when Th 2 is blocked, C 9 charges itself across two resistances R 25 , R 26 .
  • the transistor T 9 as soon as the circuit is placed under voltage, is submitted to a base polarisation voltage across a resistance R 27 . It is thus open and, being mounted in parallel to T 8 (then blocked) it lowers the striker voltage of Th 1 in such a manner as to prevent the firing of Th 1 . There is accordingly no switching.
  • a Zener diode D 18 coupled to the terminal B of C 9 across two resistances R 8 and R 30 in series, becomes unblocked (for example at 6.2 volts).
  • a condenser C 10 in series with D 18 then charges, until the moment when it polarises the base of the transistor T 7 , which become unblocked.
  • the conduction of T 7 eliminates the base current of T 9 , which becomes blocked.
  • the device T 7 -T 9 has in any event been placed out of use and the switching can take place normally in the presence of an object which breaks the beam.
  • the emitter of T 3 is coupled to the feed point B by means of a resistance R 9 , its collector being coupled on the one hand to earth across a resistance R 4 , and on the other hand to the base of T 4 .
  • the base of T 3 is polarised, starting from the voltage at B, through a resistance bridge R 10 -R 3 , the common point of which is coupled to the collector of T 4 by a time constant circuit comprising a fixed resistance R 6 in parallel with a resistance R 5 having a negative temperature coefficient, this parallel assembly being in series with a condenser C 1 .
  • the transistor T 4 is in series with the electro-luminescent diode D 1 and a resistance R 7 and the common point of these latter components is coupled to the common point between R 9 and T 3 .
  • the emitter-base current of T 3 passes through R 9 , R 5 and R 6 and progressively charges C 1 .
  • This current multiplied by the current gain of T 3 , serves as base current for T 4 and it decreases exponentially during the charging of C 1 , until it becomes insufficient to ensure the saturation of T 4 .
  • the transistor T 4 passes into a state of linear operation; its collector potential increases again and this increase of potential is transmitted, through C 1 , R 5 -R 6 to the base of T 3 , as a result of which there is blocking of this latter and, consequently, blocking of T 4 .
  • the circuit finally delivers current pulses of the order of 1A (an order of size which is suitable to give the electro-luminescent diode an acceptable range), with a cyclic ratio of the order of 1/1000 (duration of the pulses: about 4 micro-sec.; interval between pulses: 4 milli-sec.).
  • the mean current consumed by the electro-luminescent diode is thus of the order of 1 mA; the multivibrator has, for its part, a negligible consumption.
  • the duration of conduction depends upon the constant of the period of charge of C 1 across the circuit R 5 -R 6 , and upon the gain of the transistor T 3 . These two factors varying in inverse direction as the temperature increases, it is possible to keep this duration constant. In practice, it is preferable to choose the values of the parameters so that the pulses shall be a little longer at low temperatures than at medium temperatures, in order to take into account the fact that the efficiency of the photo-transistor lowers when the temperature lowers.
  • Another feature of the emitter circuit described lies in the presence of the counter-reaction resistance R 9 which couples the terminal B to the emitter of T 3 .
  • the drop of voltage in this resistance during the periods of conduction has the effect of causing the transistor T 3 to operate in linear manner, essentially unstable, which avoids any risk that the multivibrator can remain permanently in conductive state.
  • the photo-transistor T 1 connected with common collector, is polarised by a circuit comprising the resistances R 8 , R 1 and R 2 in series with a condenser C 2 mounted in parallel with R 1 , R 2 .
  • the counter-reaction inherent to the common collector circuit which considerably reduces any interference, provides for the circuit a good immunity to continuous ambient light.
  • the amplifier transistor T 2 connected with common base, has an extremely low input impedance, which increases the rapidity of the photo-transistor T 1 .
  • the components T 1 and T 2 consume only a low current.
  • a feature of the circuit of the drawing is found in the fact that the pulses, available on the collector resistance R 11 of T 2 , are not applied directly to the integrator circuit (C 7 -C 8 -R 22 -R 23 -R 24 ) but are firstly put into order by a monostable multi-vibrator composed of two complementary transistors T 5 and T 6 .
  • the elements of the circuit of this multi-vibrator (resistances R 20 , R 17 , R 19 , R 21 ; condenser C 6 , diode D 3 ) are adjusted so that the period of conduction of T 5 and T 6 shall be about equal to half of the period of the emitter circuit, for example 2 ms.
  • a circuit of the type in which the switching means would be non-conductive when the beam is broken could obviously comprise an inverter means between the integrator circuit and the transistor T 8 .
  • the protection device constituted by the transistors T 7 and T 9 could be eliminated.
US06/152,250 1979-05-25 1980-05-22 Photo-electric detector with temperature-compensated circuit Expired - Lifetime US4328419A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7913316 1979-05-25
FR7913316A FR2457604A1 (fr) 1979-05-25 1979-05-25 Detecteur photo-electrique de la presence d'un objet, du type a deux fils

Publications (1)

Publication Number Publication Date
US4328419A true US4328419A (en) 1982-05-04

Family

ID=9225858

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/152,250 Expired - Lifetime US4328419A (en) 1979-05-25 1980-05-22 Photo-electric detector with temperature-compensated circuit

Country Status (10)

Country Link
US (1) US4328419A (fr)
JP (1) JPS55159172A (fr)
BE (1) BE883409A (fr)
CH (1) CH635688A5 (fr)
DE (1) DE3019071A1 (fr)
ES (1) ES8104685A1 (fr)
FR (1) FR2457604A1 (fr)
GB (1) GB2052737B (fr)
IT (1) IT1130737B (fr)
NL (1) NL8003031A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4710622A (en) * 1984-07-31 1987-12-01 Ricoh Company, Ltd. Device for stabilizing photosensor output to varying temperature
US4745274A (en) * 1985-10-17 1988-05-17 Nissan Motor Co., Ltd. Semiconductor light detecting integrated circuit
US5541623A (en) * 1993-06-02 1996-07-30 Alps Electric (U.S.A.) Inc. Temperature compensated opto-electronic circuit and mouse using same
US5838152A (en) * 1995-07-17 1998-11-17 Matra Bae Dynamics, (Uk) Ltd. Pulse timer circuit
US20050153813A1 (en) * 2004-01-13 2005-07-14 Alexander Serkh Two speed transmission and belt drive system
US20080170007A1 (en) * 2000-09-19 2008-07-17 Semiconductor Energy Laboratory Co., Ltd. Self Light Emitting Device and Method of Driving Thereof

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2497423A1 (fr) * 1980-12-31 1982-07-02 Telemecanique Electrique Appareil detecteur du type a deux bornes, comportant un circuit d'alimentation en courant alternatif redresse et de commande d'une charge a l'aide de thyristors de commutation
DE3230903C2 (de) * 1982-08-19 1985-07-18 Erwin Sick Gmbh Optik-Elektronik, 7808 Waldkirch Schaltende Lichtschranke
DE3411995A1 (de) * 1984-03-31 1985-10-03 Kulzer & Co Gmbh, 6380 Bad Homburg Lichtschranke als schalter in einer aufnahmevorrichtung fuer ein handgeraet
DE3803034C3 (de) * 1988-02-02 1994-10-20 Sick Optik Elektronik Erwin Photoempfänger

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992622A (en) * 1974-11-25 1976-11-16 Fuji Photo Optical Co., Ltd. Logarithmic amplifier with temperature compensation means
US4153835A (en) * 1977-08-25 1979-05-08 Bell Telephone Laboratories, Incorporated Temperature compensation circuit

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3348167A (en) * 1966-04-20 1967-10-17 Avco Corp Relaxation oscillator requiring low current
FR2123753A5 (fr) * 1971-01-29 1972-09-15 Cometa Sa
DE2340978A1 (de) * 1973-08-14 1975-02-27 Licentia Gmbh Sender fuer wechsellichtschranke
DE2517597A1 (de) * 1975-04-21 1976-11-04 Stiebel Eltron Gmbh & Co Kg Schaltungsanordnung zur beruehrungslosen an- und abschaltung, insbesondere von haendetrocknern
FR2373037A1 (fr) * 1976-12-03 1978-06-30 Telemecanique Electrique Detecteur de proximite a deux fils
DE2710631A1 (de) * 1977-03-11 1978-09-14 Weber Guenther Reflexlichtschranke

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992622A (en) * 1974-11-25 1976-11-16 Fuji Photo Optical Co., Ltd. Logarithmic amplifier with temperature compensation means
US4153835A (en) * 1977-08-25 1979-05-08 Bell Telephone Laboratories, Incorporated Temperature compensation circuit

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4710622A (en) * 1984-07-31 1987-12-01 Ricoh Company, Ltd. Device for stabilizing photosensor output to varying temperature
US4745274A (en) * 1985-10-17 1988-05-17 Nissan Motor Co., Ltd. Semiconductor light detecting integrated circuit
US5541623A (en) * 1993-06-02 1996-07-30 Alps Electric (U.S.A.) Inc. Temperature compensated opto-electronic circuit and mouse using same
US5838152A (en) * 1995-07-17 1998-11-17 Matra Bae Dynamics, (Uk) Ltd. Pulse timer circuit
US20080170007A1 (en) * 2000-09-19 2008-07-17 Semiconductor Energy Laboratory Co., Ltd. Self Light Emitting Device and Method of Driving Thereof
US8686928B2 (en) * 2000-09-19 2014-04-01 Semiconductor Energy Laboratory Co., Ltd. Self light emitting device and method of driving thereof
US20050153813A1 (en) * 2004-01-13 2005-07-14 Alexander Serkh Two speed transmission and belt drive system
US20070232435A1 (en) * 2004-01-13 2007-10-04 Alexander Serkh Two speed transmission and belt drive system

Also Published As

Publication number Publication date
FR2457604A1 (fr) 1980-12-19
CH635688A5 (fr) 1983-04-15
BE883409A (fr) 1980-09-15
ES491819A0 (es) 1981-04-01
IT1130737B (it) 1986-06-18
IT8022288A0 (it) 1980-05-23
GB2052737B (en) 1983-12-07
GB2052737A (en) 1981-01-28
JPH0143279B2 (fr) 1989-09-19
NL8003031A (nl) 1980-11-27
ES8104685A1 (es) 1981-04-01
DE3019071C2 (fr) 1989-02-02
FR2457604B1 (fr) 1981-07-17
JPS55159172A (en) 1980-12-11
DE3019071A1 (de) 1980-12-04

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